I am replacing my old Quadraverb(s) which reside in the effects loop of their respective amps. Amp 1 ('63 Vox "like" circuit): I just ordered Neunaber's mono Echo and Reverb pedals. I also ordered a Ebtech LLS-2 Line Level Shifter 2-Channel Box because this amp's loop is line-level. I have no idea if this will work (TBD). Amp 2 (Marshall head): This amp's loop has an "instrument" level option. So, please recommend a high-quality Quadraverb replacement (pedal) for Amp 2. I can live with a reverb only option--although I can accommodate a reverb and delay in the budget. Thanks in advance.